Temporary masks are used to provide a coating material when manufacturing printed circuit boards. The masks are used to protect selected areas of the circuit board from the action of, for example, an acid etch, plating, such as electroplating, solder and the like. The mask is a coating which protects a portion of the circuit board during the processing thereof. Essentially, the mask prevents or restricts, for example, solder pickup or flow into those areas that are intended to be protected or free of the solder.
In the manufacture of printed circuit boards, following the application of solder or electroplating, the circuit board must be cleaned in order to properly function. Because of the miniaturization of many of the components that are affixed to circuit boards, it is necessary to maintain extremely high levels of cleanliness and strict standards to which the printed circuit boards are manufactured.
Water is a primary constituent used for cleaning printed circuit boards. In addition, in order to maintain the high standards and levels of cleanliness, the water is ultra-pure. That is, the various contaminants present in well water or other public water sources are first removed from the water prior to its use in the circuit board processing and cleaning systems. In order to prepare the water for use in these processing systems, extreme measures are taken to minimize the level of contaminants in the water. This processing of water can be quite costly and, to this end, it is desirable to maintain as much of the water within the system and to minimize make-up or re-processing in order to maintain the water inventory at an acceptable level and the contamination levels low. In order to maintain the low contaminant levels and high cleanliness standards, while maintaining the water processing costs at an economically feasible level, the water is typically maintained in a closed loop recycle system.
During the manufacturing process, the temporary masking material is washed from the printed circuit boards and removed by various steps of a water wash. After removal of the temporary mask, the water must be filtered and demineralized (e.g., ion-exchange) in order to maintain the high cleanliness standards. Known masking agents materials have ionic components. There is a great tendency for the removed masking materials to collect or agglomerate on the filtering and ion-exchange materials. Because of the ionic nature of these materials, they tend to bind to the ionic demineralization media due to the media's high affinity for the ionic materials. This phenomenon results in quickly loading the ion-exchange media beds, thus, rendering them ineffective.
Accordingly, there exists a need for an effective masking material that does not render further processing ineffective. Most desirably, such a material is non-ionic and, does not agglomerate or clump the ion-exchange or filtration media. Most desirably, such a non-ionic mask extends the life of the circuit board wash solution while maintaining high standards and levels of cleanliness and low contamination levels in the processing water.